The park's south entrance as well as the Pinto and Cottonwood Canyon roads reopened Tuesday and the Cottonwood Visitor Center was expected to reopen Wednesday, the National Park Service said.
The southern portion of the vast desert park had to be evacuated on Monday when thunderstorms unleashed the floods.
South of Joshua Tree, operators of the Palm Springs Aerial Tramway announced that the attraction that rises on the flanks of Mount San Jacinto will remain closed through Aug. 14 for cleanup of flood debris.
Earlier flooding extensively damaged roads in Death Valley National Park and the Mojave National Preserve. Highway 190, a major route into Death Valley, will reopen no earlier than Aug. 17, according to the park service.
Isolated thunderstorms were expected in the region Wednesday afternoon and evening.